condition mean min max ZT0-3 7.925215 7.925215 7.925215 ZT4-7 8.2554 8.2554 8.2554 ZT8-11 6.38337 6.38337 6.38337 ZT12-15 5.26511 5.26511 5.26511 ZT16-19 8.76062 8.76062 8.76062 ZT20-23 7.1640250000000005 7.1640250000000005 7.1640250000000005